Continuous manufacturing of polyol

Abstract

A method of continuously producing a polyol includes: (i) feeding a solid catalyst into a continuous stirred tank reactor (CSTR); (ii) contacting a reaction mixture comprising one or more epoxides and carbon dioxide with the solid catalyst and a chain transfer agent comprising a plurality of sites capable of initiating copolymerization of epoxides and carbon dioxide in the CSTR; (iii) allowing polymerization reaction to proceed until a desired molecular weight polyol has formed; and (iv) terminating the polymerization reaction.

What is claimed is: 
     
       1. A method of continuously producing a polycarbonate polyol, the method comprising:
 i) feeding a solid catalyst into a continuous stirred tank reactor (CSTR); 
 ii) adding one or more epoxides and carbon dioxide to the CSTR thereby forming a reaction mixture; 
 iii) contacting the reaction mixture comprising one or more epoxides and carbon dioxide with the solid catalyst and a chain transfer agent comprising a plurality of sites capable of initiating copolymerization of epoxides and carbon dioxide in the CSTR; 
 iv) allowing polymerization reaction to proceed until a desired molecular weight polyol has formed; and 
 v) terminating the polymerization reaction, 
 wherein a polydispersity index of the polyol is within a range from about 1.2 to about 1.45, and 
 wherein a viscosity of the polyol at 75 degrees C. is within a range from about 100 centipoise to about 10,000 centipoise. 
 
     
     
       2. The method of  claim 1 , wherein a moisture tolerance level of the polymerization reaction is within a range from about 100 ppm to about 500 ppm. 
     
     
       3. The method of  claim 1 , wherein the solid catalyst is activated prior to the feeding step. 
     
     
       4. The method of  claim 1 , wherein the solid catalyst comprises a metal coordination compound comprising a permanent ligand set and at least one ligand that is or comprises a polymerization initiator. 
     
     
       5. The method of  claim 1 , wherein the one or more epoxides and the carbon dioxide are added separately, and wherein the adding steps are continuous. 
     
     
       6. The method of  claim 1 , further comprising:
 continuously providing the chain transfer agent to the CSTR; and continuously supplying a solvent to the CSTR. 
 
     
     
       7. The method of  claim 1 , further comprising:
 separating the solid catalyst after the terminating step, 
 wherein the solid catalyst is removed via an ionic exchange resin. 
 
     
     
       8. The method of  claim 1 , further comprising:
 discharging the polycarbonate polyol from the CSTR after the polymerization reaction, and 
 separating the polycarbonate polyol. 
 
     
     
       9. The method of  claim 1 , wherein a flow rate of the carbon dioxide is within a range from about 20 g/h to about 100 g/h. 
     
     
       10. The method of  claim 9 , wherein a production rate of the polycarbonate polyol is within a range of about 200 g/h to about 1000 g/h,
 wherein a number average molecular weight of the polycarbonate polyol is within a range of about 750 to about 1500 g/mol, and 
 wherein a residence time of the reaction mixture is within a range of about 12 hours to about 24 hours. 
 
     
     
       11. A polyol obtained by and/or obtainable by the method of  claim 1 . 
     
     
       12. A method of continuously producing a polycarbonate polyol, the method comprising:
 i) feeding a solid catalyst into a continuous stirred tank reactor (CSTR); 
 ii) adding one or more epoxides and carbon dioxide to the CSTR thereby forming a reaction mixture; 
 iii) contacting the reaction mixture comprising one or more epoxides and carbon dioxide with the solid catalyst and a chain transfer agent comprising a plurality of sites capable of initiating copolymerization of epoxides and carbon dioxide in the CSTR; 
 iv) allowing polymerization reaction to proceed until a desired molecular weight polyol has formed; and 
 v) terminating the polymerization reaction 
 where a moisture level of the reaction mixture is below a moisture tolerance level of the polymerization reaction, and 
 wherein the method does not include drying either the reaction mixture or the chain transfer agent prior to the polymerization reaction. 
 
     
     
       13. A method of continuously producing a polycarbonate polyol, the method comprising:
 i) feeding a solid catalyst into a continuous stirred tank reactor (CSTR); 
 ii) adding one or more epoxides and carbon dioxide to the CSTR thereby forming a reaction mixture 
 iii) contacting the reaction mixture comprising one or more epoxides and carbon dioxide with the solid catalyst and a chain transfer agent comprising a plurality of sites capable of initiating copolymerization of epoxides and carbon dioxide in the CSTR; 
 iv) allowing polymerization reaction to proceed until a desired molecular weight polyol has formed; and 
 V terminating the polymerization reaction 
 wherein there is no observable induction time of the solid catalyst subsequent to reactor startup, and 
 wherein the solid catalyst is not activated prior to the feeding step.